This research focuses on the changing role of requirements engineering, from one that not only considers functional and non-functional requirements, as has traditionally been the case, but also the interplay between business and system functionality. Whether a business wishes to exploit advances in technology to achieve new strategic objectives or to organise work in innovative ways, the process of requirements engineering can and should present opportunities for modelling and evaluating the potential impact that technology can bring to an enterprise through a process of co-development. (0- development aims to ensure alignment between enterprise and Information Systems goals and requirements. However a number of challenges are faced during codevelopment projects, emanating from the engagement of multiple stakeholders from differing organisations, subcontractors, divisions, etc, who have different experiences, skills and frequently competing goals. Stakeholders are faced with many different alternative future 'worlds', each potentially demanding different development strategies. Furthermore questions are raised about the potential structure of the new business system and how key variables in this structure could impact on the dynamics of the system. This thesis introduces and develops a framework to deal with the aforementioned issues. This framework called, the Requirements Elaboration Framework is proposed to enable the modelling and evaluation of the impact of reqUirements on the enterprise. The framework comprises System Dynamics, ontology, scenario and rationale modelling. Behaviour of the enterprise system is defined within the System Dynamics model. Invariant components of the physical and social world, in the enterprise and application domain, are formally defined within the ontology model. Scenario modelling is used to identify critical variables. Quantitative analysis of the effects of such variables through simulation enables a better understanding of the dynamic behaviour of possible future structures. Assumptions and reasoning behind key decisions are charted within the rationale model. This assists with collaborative stakeholder discussions during ontology and scenario modelling. A case study, which focuses on the liberalisation of electricity in the European Union, is used to illustrate the workings of the proposed framework.